Pilot study of targeting magnetic carbon nanotubes to lymph nodes

Aim: The lymphatic distribution of magnetic carbon nanotubes was studied in vivo and compared with magnetic-activated carbon particles, which were selectively taken up in the lymphatic channels and delivered to the regional lymph nodes. Material & methods: Magnetic multiwalled carbon nanotubes functionalized with poly(acrylic acid) (mMWNTs) and magnetic-activated carbon particles were subcutaneously injected in mice. The draining lymph nodes were harvested at different times postadministration to examine the lymphatic distribution of these particles. The short-term accumulation and toxicity of mMWNTs in the major organs were studied. Results: mMWNTs had the same properties of lymph node mapping as magnetic-activated carbon particles in mice independent of lymph node metastasis. The degree of black staining of lymph nodes and concentration of mMWNTs had a dose-response relationship. Aggregation of magnetic particles was found around the metastatic foci within the lymph nodes. Footpad injection of mMWNTs did not cause any obvious local or systemic toxicities, and no particle agglomerates were found in the major organs. Conclusion: The feasibility of targeting magnetic carbon nanotubes to lymph nodes was demonstrated and the results support further studies for their potential use in diagnosing and treating cancer.